We're slowly rounding the corner of the long year and a half to the official iPhone SDK. Momentum has been growing and growing; Apple's main iPhone SDK site is now at positions 2 and 3 on Google for "SDK". Cocoa developers are tweeting away at all of the possibilities for the iPhone once the proper SDK is released, and there's quite a few who throw out the term "game-changer".
But fuck it. It's mid-May and by golly, who wants to wait. Installer.app has been around for months now, and it's really matured. It serves as a virtual "AppStore" until the real deal comes along, and lets you install, update, and uninstall apps on the fly. These aren't the officially-supported web-based apps that have been around for half a year or so; these apps run native on your phone. So, until the floodgates open up around WWDC, let's take a peek at some of the cooler native apps out there right now.
Twinkle
Twinkle is a location-aware Twitter client. It taps into the same technology that powers the latest Google Maps update: it uses your surrounding wifi connections in conjunction with cell phone tower triangulation to come up with your location. When I start up Twinkle, I can see the number of recently-made tweets made "near me", which is a rather interesting aspect added on top of Twitter. When I was on campus at Carnegie Mellon, I chatted with a few different perspective students who were on-campus doing their college visits. Answered a few questions, offered to meet up (though our timing didn't work out), that type of thing. Another time I was driving a few hours into Ohio to enjoy an excellent day at Cedar Point (best roller coasters in the world), and I was able to strike up a conversation with a few people just by driving along the interstate and stumbling on random tweets as I went. It certainly makes for some interesting it's-a-small-world-out-there experiences.
Another cool thing is that Twinkle lets you attach images to your tweets. Other Twinkle users can see your posted image, and I believe they've since added a way for regular Twitter, non-Twinkle users to see it online, too.
StreetFlow
StreetFlow is relatively new, coming on the scene a few weeks ago. It's one of my favorite apps, and it's something that could really benefit from a greater number of active users. Think of it as a social restaurant app. There's a few of them online already, but having a simple one in your pocket is pretty helpful. Like Twinkle, it's location-aware, so it can give you a listing of restaurants closest to you. It also has reviews, so other users can rate and review those restaurants and help out the cloud. You can also take a snapshot and attach it to the restaurant's profile, although I think there's a fair amount of functionality that needs fleshing out there.
It's an app that is pretty cool, but given the AppStore and a few hundred thousand or million people more, it could be really good. I'm not sure how much the developer is intending to continue work on StreetFlow, but if it becomes abandonware, it shouldn't be a huge problem for someone else to recreate it with a proper SDK. If iPhone 2.0 has built-in GPS, StreetFlow could be even more useful, too.
MobileScrobbler
If you're a Last.fm user, MobileScrobbler is a bit of a natural extension for you. I've usually had issues with the Last.fm OS X client when it comes to getting my iPod-listened tracks added on my Last.fm listening history. MobileScrobbler handles that for you: when you play a song on your iPhone, it will send that off to Last.fm's servers in the background and you'll then see the track added to your play history. It was a pretty seamless process; it took me a good two or three days before I even noticed that it was scrobbling tracks in the background for me.
On top of that, you score some pretty crazy music streaming capabilities. You can stream your playlist, your neighborhood, or recommended tracks. It acts like the normal music player at that point—you can lock your screen, get up, take a walk, and so on (provided you still have access to wireless).
Tap Tap Revolution
Okay, I'm not one of those guys that really get sucked into Dance Dance Revolution or Guitar Hero or Rock Band or anything. I've enjoyed about three hours on Guitar Hero, but that's about it. Tap Tap Revolution is the natural evolution of DDR on the iPhone. It's surprisingly pretty fun. Two cool aspects here: the songs come from your own library, and the other is that the beats to those songs comes from other iPhone users. It's pretty straightforward, fun, and if my friends are any indication, the one app that people steal my iPhone away from me the longest to play.